The FAA has approved the iPad as a replacement for paper maps in the cockpits of commercial aircraft. Traditionally, airline pilots have carried reams of the maps of the airports they were flying into and out of, in a specialized flight suitcase. Now they will really only need their iPad complete with the appropriate maps application such as the one from Jeppesen.
According to an article in Bloomberg (http://bloom.bg/fFwLkH), Delta Airlines is one of the major players in the push to get the iPad approved by regulators. Obviously with flight computers being much heavier and bulkier, the iPad with its crystal clear screen and easy to use interface makes it the perfect lightweight candidate to replace all of the other items long used.
The only issue with using them in flight will be the obvious power requirements but airlines will likely set up charging stations within the cockpit for the pilots to charge their iPads and keep them flight ready.